1. Field of the Invention
This invention relates generally to a voice messaging system. More particularly, it relates to a voice messaging system having archival capability with removable digital voice message memory.
2. Description of Related Art
Today, many people use a digital telephone answering device (digital TAD) or voice mail system to receive and play back voice messages. A conventional digital TAD is typically a stand-alone device which records voice messages from one or two telephone lines in permanently installed digital voice memory (i.e., RAM). A voice mail system is typically used in conjunction with a private branch exchange (PBX) to provide voice messaging capability to a plurality of users. The present invention, while being described herein below with respect to a telephone answering device, is applicable to voice messaging systems in general, including voice mail systems.
FIG. 5 illustrates a conventional voice messaging system such as a digital TAD 200. The conventional digital TAD 200 typically includes a processor 202 for controlling overall functions of the digital TAD 200, and a digital signal processor (DSP) 204 primarily for handling voice processing.
In the conventional fashion, the processor 202 communicates with the DSP 204 using respective serial interfaces 202a, 204a. The processor 202 is connected to read only memory (ROM) 206 containing program code for operation of the processor 202, and random access memory (RAM) 208 for storing variables and other temporary information. A keypad accessible by the user of the digital TAD 200 allows the user to control aspects of the digital TAD 200, e.g., playback and deletion of previously recorded voice messages.
The DSP 204 is connected to ROM 210 containing program code for operation of the DSP 204, and RAM 212 for storage of temporary information primarily for use by the DSP 204. The DSP 204 operates in response to a predetermined program of instructions stored in ROM 210. The DSP 204 also includes a tone generator algorithm to provide DTMF tones to the telephone line 230, and a DTMF detector algorithm to detect DTMF tones. The DSP 204 may also provide a time and date stamp obtained either from a local clock or from call related information (e.g., Caller ID information) received from the telephone company.
The RAM 212 of the DSP 204 includes permanently installed voice memory 212a for storage of digital voice messages. Voice messages are recorded and deleted from the voice memory 212a as desired. Desired voice messages are played back by a voice message recorder/playback module 220, which is connected to a speaker 224 for playback, and to a microphone 222 for recording outgoing message greetings and memos in voice memory.
RAM 208 and/or RAM 212 may be flash memory, dynamic random access memory (DRAM), static random access memory (SRAM), or other suitable re-writable memory. To reduce the physical memory requirements in the digital TAD 200, the DSP 204 includes coding procedures to compress the digital voice messages before storage in the voice memory 212a. The DSP 204 also includes complementary decoding procedures to decompress the digital voice messages for playback by the voice message recorder/playback module 220. Suitable coding/decoding techniques include linear predictive coding (LPC), code excited linear prediction (CELP), vector sum excited linear predictive (VSELP) coding, adaptive differential pulse code modulation (ADPCM), xcexc-law, or A-law, to name a few. The preferable coding/decoding techniques minimize the amount of data required to represent a voice message at xe2x80x9ctoll qualityxe2x80x9d or better.
The digital TAD 200 further includes an analog-to-digital (A/D) converter 214 and a digital-to-analog (D/A) converter 216 for conversion of signals received from a telephone line 230 to and from digital format for processing by the DSP 204. The A/D converter 214 and/or D/A converter 216, although shown external to the DSP 204, may be integrated within the DSP 204. The digital TAD 200 interfaces to the telephone line 230 through a telephone line interface (TLI) 218.
The digital TAD 200 may be controlled by keypad entries entered on a telephone keypad 226 or by dual tone, multiple frequency (DTMF) tones received from remote locations over telephone line 230.
In operation, the TLI 218 of the digital TAD 200 causes an off-hook condition on the telephone line 230 subsequent to receiving a predetermined number of ring signals on the telephone line 230. At that point, the DSP 204 retrieves a previously stored outgoing greeting message (OGM) from the permanently installed voice memory 212aportion of the DSP""s RAM 212, and provides the same to the D/A converter 216 for output to the telephone line 230 via the TLI 218. Upon conclusion of the OGM, the caller may leave a voice message for recording in the digital TAD 200. The incoming voice message is converted into a digital signal by the A/D converter 214, and stored in the permanently installed voice memory 212a portion of the RAM 212 of the DSP 204.
Unfortunately, the options as to what may be done with the recorded voice message are limited in the conventional digital TAD 200. For instance, the user may playback the voice message through the voice message recorder/playback module 220 and speaker 224, or may depress a key or keys on keypad 226, or controlled from a remote location, e.g., via DTMF tones, to cause deletion of the voice message from voice memory 212a. 
It is sometimes desirable to permanently archive or otherwise physically remove a previously recorded voice message from a digital TAD 200. For instance, it may be desirable to maintain a copy of a message left on the digital TAD 200 for maintaining a record of calls from an unwanted caller. It might also be desirable to record a conversation between two parties talking over the telephone line 230, and to playback the conversation at a location remote from the digital TAD 200 and even remote from a telephone line. However, replay of the recorded conversation in a conventional digital TAD 200 is limited to playback at the digital TAD 200 itself or a telephone in communication with the digital TAD 200.
There is a need for a voice messaging system having the flexibility to allow removal and archival of a voice message recorded at the voice messaging system. There is also a need to provide a voice messaging system which allows convenient playback of a voice message recorded at a voice messaging system, on a separate listening device remote from the digital TAD and the telephone system.
In accordance with the principles of the present invention, a digital voice memory module for a voice messaging system comprises non-volatile memory, and a separable connector allowing an operable disconnection of the non-volatile memory from a data bus of the voice messaging system.
In another aspect, the present invention provides a voice messaging system including a processor, a voice message recorder/playback module, and a telephone line interface in communication with the voice message recorder/playback module. The system further includes an externally accessible interface in communication with the processor, and allows for installation of a removable voice memory module in connection with the externally accessible interface.
A method and means for recording and archiving a voice message in a voice messaging system is also provided in accordance with the principles of the present invention. A voice message is received and stored in a removable digital memory module. Thereafter, the removable digital memory module is allowed to be removed from the voice messaging system.